Frymaster Dean FPHD - Manual (Page 8)

HIGH EFFICIENCY DECATHLON SERIES GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-3
Electronic Ignition Configuration (cont.)
At start-up the ON/OFF switch is placed in the ON position, supplying 12 VDC to the heat control
circuitry in the controller or computer and to one side of the heat relay coil on the interface board. If
resistance in the temperature probe indicates the temperature in the frypot is below 180°F (82°C),
the current flows through a melt cycle circuit where a timer switch alternately closes for 3 seconds
and opens for 24 seconds. If the temperature is 180°F (82°C) or above, the current flows through a
heat circuit, bypassing the timer switch. In either case, current is supplied to the other leg of the heat
relay coil which then closes an electronic switch in the 24 VAC circuit to provide current to the
ignition module. NOTE: The listed melt cycle times and exit temperature pertain to the Compu-Fry
computer only.
Circuitry in the ignition module sends 24 VAC current to the gas valve via a normally closed high-
limit switch and a drain safety switch. Simultaneously, the module causes the ignitor to spark for up
to 90 seconds to light the pilot flame. A flame sensor verifies that the pilot is lit by measuring the
flow of microamps through the flame. If the pilot does not light (or is extinguished), current to the
ignition module is interrupted, preventing the main valve from opening, and the ignition module
"locks out" until the power switch is turned OFF, then back ON.
A temperature probe monitors the temperature in the frypot. When the programmed setpoint
temperature is reached, resistance in the probe causes the heat cycle circuitry in the controller to
interrupt current flow through the heat relay. This in turn interrupts the 24 VAC current to the
ignition module, resulting in closure of the gas valve.
NOTE: Unlike previous modules, microamp readings on these black modules will move up and
down as the module pulses on and off and this is an indication that the module is functioning.
Control Options
HD Series gas fryers may be equipped with Thermatron controls or Compu-Fry computers.
In fryers equipped with Thermatron controls, the fryer is turned on and off by means of a rocker
switch and the temperature is set by adjusting a potentiometer. An interface board is located in the
component box (shield) behind the control panel (computer-equipped) or a Thermatron board is
located in a component box inside the cabinet (Thermatron-equipped).
Interface Boards
The interface board provides a link between the controller/computer and the fryer’s individual
components without requiring excessive wiring, and allows the controller to execute commands
from one central point. Two types of interface boards may be used in HD Series gas fryers; the type
used depends on the fryer configuration.
In units configured for electronic ignition and constant pilot, P/N 106-6669 is used; in units
configured with a manually lit pilot (non-electronic ignition), P/N 106-6710 is used.